Method of Defining Electrodes Using Laser-Ablation and Dielectric Material

ABSTRACT

A method of forming an electrochemical test sensor includes providing a base. Electrochemically-active material is placed on the base. Dielectric material is applied over the electrochemically-active material. A first selected area of the dielectric material is laser-ablated to expose the electrochemically-active material. A second selected area of the dielectric material and the electrochemically-active material are laser-ablated to expose the base. The first selected area is different from the second selected area. A second layer is applied to assist in forming a channel in the test sensor. The channel assists in allowing a fluid sample to contact a reagent located therein. The dielectric material is located between the base and the second layer.

FIELD OF THE INVENTION

The present invention generally relates to a method of forming a testsensor. More specifically, the present invention generally relates to amethod of forming an electrochemical test sensor that is adapted toassist in determining a concentration of an analyte by using laserablation.

BACKGROUND OF THE INVENTION

The quantitative determination of analytes in body fluids is of greatimportance in the diagnoses and maintenance of certain physiologicalabnormalities. For example, lactate, cholesterol and bilirubin should bemonitored in certain individuals. In particular, it is important thatdiabetic individuals frequently check the glucose level in their bodyfluids to regulate the glucose intake in their diets. The results ofsuch tests can be used to determine what, if any, insulin or othermedication needs to be administered. In one type of blood-glucosetesting system, test sensors are used to test a sample of blood.

A test sensor contains biosensing or reagent material that reacts withblood glucose. One type of electrochemical test sensor is a multilayertest sensor that includes a base or substrate and a lid. Another type ofelectrochemical test sensor includes a base, a spacer and a lid.Existing electrochemical test sensors include at least two electrodes inthe form of an electrode pattern. A potential is applied across theseelectrodes and a current is measured at the working electrode. Thecurrent measurement is directly proportional to the size of the workingelectrode.

The accuracy of the electrochemical test sensor is typically improved ifthe area of the working electrode can be precisely defined in thetest-sensor manufacturing process. Currently, an electrode pattern(including the working electrode) is typically defined on a base on oneaxis by the electrode-defining technique (i.e., printing orlaser-ablation) and the other axis is defined by a second layer (a lidor a spacer) that is attached to the base. The act of attaching the baseand the lid or spacer often has high, less desirable tolerances. Forexample, the laminating of the base and the lid or spacer tends to havevariances that are less than desirable (i.e., +/−0.005 in.). The use oflaser-ablation, on the hand, has a more desirable tolerance (i.e.,+/−0.0005 inch). Thus, the tolerance in the lid or spacer placement thenbecomes the significant factor influencing the precision of forming theworking-electrode area.

Therefore, it would be desirable to use a method that improves theaccuracy of the test-sensor-based system by better defining the workingelectrode. It would also be desirable to enhance the within-lotreproducibility of the manufacturing process.

SUMMARY OF THE INVENTION

According to one method, an electrochemical test sensor is formed thatincludes providing a base. Electrochemically-active material is placedon the base. The electrochemically-active material is laser-ablated toform an electrode pattern. Dielectric material is placed over theelectrode pattern. Selected areas of the dielectric material arelaser-ablated to expose a portion of the electrode pattern. A secondlayer is applied to assist in forming a channel in the test sensor. Thechannel assists in allowing a fluid sample to contact a reagent locatedtherein. The dielectric material is located between the base and thesecond layer.

According to another method, an electrochemical test sensor is formedthat includes providing a base. An electrode pattern is formed on thebase. Dielectric material is applied over the electrode pattern.Selected areas of the dielectric material are laser-ablated to expose aportion of the electrode pattern. A second layer is applied to assist informing a channel in the test sensor. The channel assists in allowing afluid sample to contact a reagent located therein. The dielectricmaterial is located between the base and the second layer.

According to a further method, an electrochemical test sensor is formedthat includes providing a base. Electrochemically-active material isplaced on the base. Dielectric material is applied over theelectrochemically-active material. A first selected area of thedielectric material is laser-ablated to expose theelectrochemically-active material. A second selected area of thedielectric material and the electrochemically-active material arelaser-ablated to expose the base. The first selected area is differentfrom the second selected area. A second layer is applied to assist informing a channel in the test sensor. The channel assists in allowing afluid sample to contact a reagent located therein. The dielectricmaterial is located between the base and the second layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a top view of an electrochemical test sensor according toone embodiment.

FIG. 1 b is a side view of the electrochemical test sensor of FIG. 1 a.

FIG. 1 c is a top view of the base to be used in the electrochemicaltest sensor of FIG. 1 a.

FIG. 2 a is a top view of an electrochemical test sensor according toanother embodiment.

FIG. 2 b is a side view of the electrochemical test sensor of FIG. 2 a.

FIGS. 3 a-3 h is a sequence of steps in forming an electrochemical testsensor according to one process.

FIGS. 4 a-4 i is a sequence of steps in forming an electrochemical testsensor with a spacer according to one process.

FIGS. 5 a, 5 b are a few steps in a sequence of steps to be used informing an electrochemical test sensor according to another process.

FIGS. 6 a-6 i is a sequence of steps in forming an electrochemical testsensor according to a further process.

FIGS. 7 a-7 j is a sequence of steps in forming an electrochemical testsensor with a spacer according to a further process.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The present invention is directed to a method of improving the accuracyof an electrochemical test-sensor-based system. The present invention isalso directed to enhancing the within-lot reproductibility of themanufacturing process. More specifically, the present invention isdirected to improving accuracy and precision of the test-sensor-basedsystem by better defining the electrode pattern using a laser-ablationact. By better defining the electrode pattern, more precise readings ofan analyte concentration are obtained.

The present invention is directed to also improving the accuracy of notonly the electrode pattern, but also of the conductive leads and thetest sensor contacts. The defining of the electrode pattern and, morespecifically, the working electrode area also may reduce product cost,while at the same time reducing the volume of the fluid sample. The costand the volume of the sample are reduced because of the accuracy of theedge quality in the electrode pattern. By having a more accurate definedarea, the working electrode area may be smaller, which leads to areduced amount of chemistry and fluid sample to be used in the analysis.

The electrochemical test sensors are adapted to receive a fluid sampleand be analyzed using an instrument or meter. The test sensor assists indetermining the concentrations of analytes. Analytes that may bemeasured include glucose, cholesterol, lipid profiles, microalbumin,urea, creatinine, creatine, fructose, lactate, or bilirubin. It iscontemplated that other analyte concentrations may be determined. Theanalytes may be in, for example, a whole blood sample, a blood serumsample, a blood plasma sample, other body fluids like ISF (interstitialfluid) and urine, and non-body fluids.

The electrochemical test sensors to be made using the inventive processinclude at least a base, an electrochemically-active conductive layerfor the electrodes, dielectric material and a second layer such as a lidand/or a spacer. In one embodiment, the electrochemical test sensorsinclude a base, an electrochemically-active conductive layer for theelectrodes, dielectric material and a lid. In another embodiment, theelectrochemical test sensors include a base, an electrochemically-activeconductive layer for the electrodes, dielectric material, a spacer and alid.

The base, spacer and lid may be made from a variety of materials such aspolymeric materials. Non-limiting examples of polymeric materials thatmay be used to form the base, spacer and lid include polycarbonate,polyethylene terephthalate (PET), polystyrene, polyimide, andcombinations thereof. It is contemplated that the base, spacer and lidmay be independently made of other materials. Theelectrochemically-active surface on the base may be made from a varietyof conductive materials including, but not limited to, carbon, gold,platinum, palladium or combinations thereof.

One non-limiting example of an electrochemical test sensor is shown inFIGS. 1 a-1 d. FIGS. 1 a, 1 b depict an electrochemical test sensor 10that includes a base 12 with conductive material, dielectric material 16and a lid 20. FIG. 1 c depicts the base 12 without dielectric materialand a lid. Referring back to FIG. 1 b, a channel 22 (e.g., capillarychannel) is formed when the base 12 and the lid 20 are attached to eachother. The capillary channel 22 provides an enclosed flow path forintroducing the sample into the test sensor 10 and eventually contactingthe electrodes 30, 32, 34 and, thus, forms a reaction zone.

As shown in FIG. 1 a, the test sensor 10 includes a reactive orfluid-receiving area 50 that contains an enzyme. The enzyme is selectedto react with the desired analyte or analytes to be tested so as toassist in determining an analyte concentration of a fluid sample. Thereactive area 50 includes a reagent for converting an analyte ofinterest (e.g., glucose) in a fluid test sample (e.g., blood) into achemical species that is electrochemically measurable, in terms of theelectrical current it produces, by the components of the electrodepattern.

The reagent typically contains an enzyme (e.g., glucose oxidase), whichreacts with an analyte (e.g., glucose) and with an electrochemicalmediator (e.g., ferricyanide) to produce an electrochemically measurablespecies that can be detected by the electrodes. The reactive area 50 maycomprise a polymer, an enzyme, and an electron acceptor. The reactivearea 50 also may include additional ingredients such as a buffer and asurfactant in some embodiments of the present invention. It iscontemplated that other enzymes may be used to react with glucose suchas glucose dehydrogenase. If the concentration of another analyte is tobe determined, an appropriate enzyme is selected to react with theanalyte.

The base 12 of FIG. 1 c includes conductive material and, morespecifically, a plurality of electrodes 30, 32, 34, a plurality ofconductive leads or traces 40, 42 and test-sensor contacts 44, 46. Theplurality of electrodes of FIG. 1 c includes at least a counterelectrode 30 and a working electrode 32 according to this embodiment.The working electrode measures the current when a potential is appliedacross the working and counter electrodes. The counter electrode shouldbe sufficiently large so as to support the reaction occurring at theworking electrode. The applied voltage may be referenced to the reagentdeposited adjacent to the counter electrode.

Other electrodes such as a trigger electrode 34 are shown in FIG. 1 c.It is contemplated that other electrodes may be used. For example, anelectrochemical test sensor may include a detection electrode thatdetects an underfill condition. The electrochemical test sensor may alsoinclude a hematocrit electrode that assists in correcting for the biasthat occurs with selected hematocrit concentrations. Additionalelectrodes include, but are not limited to, electrodes that detect otheranalytes or species that may potentially interfere with the measurementof the desired analyte. Also, a second working electrode that assists indetermining the concentration of another analyte may be used.

It is contemplated that more or less electrodes can be formed in themethod of the present invention. For example, the electrochemical testsensor may include exactly two electrodes or at least three electrodes.The exactly two electrodes may be a working electrode and a counterelectrode in which an electrochemically created current flow when theseelectrodes are electrically connected and a potential is created betweenthem.

The electrodes are formed of conductive materials such as, for example,metallic materials (e.g., gold, platinum, palladium, rhodium, ruthenium,or combinations thereof) or carbon. Examples of components ofelectrochemical test sensors, including their operation, may be foundat, for example, U.S. Pat. No. 6,531,040. It is contemplated that othercomponents of electrochemical test sensors may be used other than thatdisclosed in, for example, U.S. Pat. No. 6,531,040.

The dielectric material assists in insulating electrochemically-activematerial on the base. The dielectric material may be made from a varietyof materials and methods such as, for example, sputtered dielectriccoatings (e.g., titanium aluminum nitride, titanium dioxide and silicondioxide), slot-die coating, gravure printing, spin coating,screen-printed polymeric materials solutions or inks (e.g., fluorinatedpolymers, parylene polymers and acrylics). It is contemplated that otherdielectric materials may be used such as other commercially availabledielectric coatings.

Another non-limiting example of an electrochemical test sensor is shownin FIGS. 2 a, 2 b. FIGS. 2 a, 2 b depict an electrochemical test sensor100 that includes a base 112 with conductive material, dielectricmaterial 116, a spacer 118 and a lid 120. The base 112 and thedielectric material 116 may be the same or similar to the base 12 andthe dielectric material 16 discussed above. A channel 122 (e.g.,capillary channel) is formed when the base 112, the dielectric material116, the spacer 118 and the lid 120 are attached to each other. Thecapillary channel 122 provides an enclosed flow path for introducing thesample into the test sensor 100 and eventually contacting the electrodesand, thus, forms a reaction zone.

The electrodes formed on the base 112 may be the same as described abovewith respect to the base 12. The electrodes include a counter andworking electrode in one embodiment. In other embodiments, theelectrodes may include additional electrodes such as the above discussedtrigger electrode, detection electrode, hematocrit electrode, a secondworking electrode and other electrodes.

The present invention is directed to an inventive process for forming anelectrochemical test sensor. In one method, the electrochemical testsensors may be formed from ribbon strips. The ribbon strips may be madefrom processes such as a multiple-sheet process or a web process. Forexample, in an embodiment with a base, dielectric material, spacer andlid, a base-ribbon strip, a dielectric-ribbon strip, a spacer-ribbonstrip and a lid-ribbon strip may be used. For improved efficiency, theelectrochemical test sensors are generally formed after all of theribbon strips have been attached. In another embodiment, the base-ribbonstrip is adapted to be attached (e.g., laminated) with a second layersuch as, for example, a lid-ribbon strip.

According to one method, an electrochemical test sensor is formed. Themethod includes providing a base and placing electrochemically-activematerial on the base. The electrochemically-active material islaser-ablated to form an electrode pattern. Dielectric material isapplied over the electrode pattern. Selected areas of the dielectricmaterial are laser-ablated to expose a portion of the electrode pattern.A second layer is applied to assist in forming a channel (e.g., acapillary channel) in the test sensor. The capillary channel assists inallowing a fluid sample to contact a reagent located therein.

The electrochemically-active material is placed or located on the baseand is generally from about 50 to about 500 Angstroms (Å) in thicknessand, more typically, from about 150 to about 350 Angstroms (Å) inthickness. The electrochemically-active material may be located on thebase using, for example, physical vapor deposition (e.g., sputtering),chemical vapor deposition (cvd), screen printing or a laminated metallicfoil.

The electrode pattern may be defined by using a mask and a laser suchas, for example, an Excimer laser, solid state, YAG (singled, doubled ortripled frequency) or a carbon dioxide-based laser. One example of amask is a chrome-on-glass mask in which a beam of light is only allowedto pass through selected areas.

According to another method, the electrode pattern may be formed with alaser using direct writing of the lines. In a method using a laser withdirect writing of the lines, a laser beam of light is moved so as todefine the electrode pattern. The laser may define, for example, theplurality of electrodes, the conductive leads and the meter contacts.Lasers that produce a beam of energy capable of removing a layer andthat can be moved to form an electrode pattern may be used in thismethod. Non-limiting examples of such lasers are carbon dioxide-basedlasers and all yttrium-based lasers such as yttrium aluminum garnet(YAG) lasers.

After the electrode pattern has been formed in this method, thedielectric material is applied to insulate the electrode pattern. Thedielectric material may be applied by methods such as physical vapordeposition (e.g., sputtering), chemical vapor deposition (cvd), spincoating, slot-die coating, reverse roll, or printing (e.g., gravure orscreen printing).

A second laser ablation is used to remove selected areas of thedielectric material to expose a portion of the electrode pattern. Thus,in this process, the entire electrode area used for the electrochemicaldetection of an analyte is defined by laser ablation of the dielectricmaterial. The second laser ablation also may expose the test-sensorcontacts.

In other embodiments, the test-sensor contacts may be formed by a firstlaser ablation or a printed conductive layer to attach to conductiveleads made from the laser ablation. In another embodiment, thetest-sensor contacts may be formed by a mask that blocks this area fromthe dielectric coating. Depending on the dielectric material, the secondlaser ablation act may be performed in a similar or the same manner asthe laser-ablation act that forms the electrode pattern from theelectrochemically-active material. For example, the first and secondlaser-ablation acts may be performed at different intensities and/orusing a different number of pulses. It is contemplated that the separatelaser-ablation acts may be performed uses differentcharacteristics/features.

In one process, the reagent may be applied to the electrode surfaces.The reagent may be applied to the electrode surface by, for example,gravure or screen printing, microdepositing (e.g., ink-jet spraying) andcoating (e.g., slot coating). The reagent may also be located on othersurfaces such as dielectric material or a second surface such as a lidor spacer. In any of these embodiments, the reagent would need tocontact the fluid sample, such as by using a capillary channel.

The base is then attached to a second layer. In one embodiment, the baseis attached to a lid. As discussed above, the base and the lid may be inthe form of respective ribbon strips. In another embodiment, the base isattached to a spacer. As discussed above, the base and the spacer may bein the form of respective ribbon strips. According to anotherembodiment, the second layer may be a spacer-lid combination. Thespacer-lid combination may be in the form of a ribbon strip (combinationof spacer-ribbon strip and lid-ribbon strip) that has been previouslyformed before being attached to the base-ribbon strip. If ribbon stripsare used, the test sensors may be excised using a mechanical punch orother methods.

The base may be attached to the second layer (e.g., lid or spacer)using, for example, a pressure-sensitive adhesive and/or a hot meltadhesive. Thus, the attachment between the base and the second surfaceuses pressure, heat or the combination thereof. It is contemplated thatother materials may be used to attach the base to the second surface. Itis also contemplated that the base and the second surface may beattached using ultrasonic energy or solvent welding.

Referring to FIG. 3 a-3 h, a method of forming an electrochemical testsensor 200 is depicted. Referring to FIGS. 3 a, 3 b, a base or substrate210 is shown in which an electrochemically-active material 220 has beenplaced thereon. As shown in FIG. 3 a, the electrochemically-activematerial 220 covers the entire base 210 in this embodiment. Referring toFIG. 3 c, the electrochemically-active material 220 is laser-ablated toform an electrode pattern 228. The electrode pattern 228 includes aplurality of electrodes. More specifically, the electrode pattern 228includes a counter electrode 230, a working electrode 232, and a triggerelectrode 234. A portion of the electrochemically-active material 220remaining after the laser-ablating act forms a plurality of conductiveleads 240, 242 and a plurality of test-sensor contacts 244, 246. Theconductive leads 240, 242 assist in establishing electricalcommunication between the electrodes and the test-sensor contacts 244,246. The test-sensor contacts 244, 246 are electrically connected withmeter contacts (not shown) and assist in conveying information of theanalyte to the meter to assist in, for example, determining the analyteconcentration.

In this method, after the electrode pattern 228 is formed, a dielectricmaterial 250 is placed over the electrode pattern as depicted in FIG. 3d. The dielectric material 250 insulates the electrode pattern 228.Referring to FIG. 3 e, selected areas of the dielectric material 250 arelaser ablated to expose at least a portion of the electrodes. Theexposed electrode patterns are shown as generally circular areas 230 a,232 a, 234 a in FIG. 3 e. It is contemplated that other polygonal ornon-polygonal shapes of the electrodes may be exposed by the laserablation. In FIG. 3 e, the dielectric material 250 in this process isalso laser ablated to expose the test-sensor contacts 244, 246. Thus, inthis method, two separate and distinct laser-ablation acts areperformed. After the exposure of the electrodes in the secondlaser-ablation act, a second layer is applied. For example, in FIGS. 3f-3 h, a lid 270 is attached to the dielectric material 250 and forms anopening 272 (see FIG. 3 h) to receive a fluid.

Referring to another method, an electrochemical test sensor 300 isformed in FIGS. 4 a-4 i. Referring to FIGS. 4 a, 4 b, a base orsubstrate 310 is shown in which an electrochemically-active material 320has been placed thereon. As shown in FIG. 4 a, theelectrochemically-active material 320 covers the entire base 310 in thisembodiment. Referring to FIG. 4 c, the electrochemically-active material320 is laser-ablated to form an electrode pattern 328. The electrodepattern 328 includes a plurality of electrodes. More specifically, theelectrode pattern 328 includes a counter electrode 330, a workingelectrode 332, and a trigger electrode 334. A portion of theelectrochemically-active material 320 remaining after the laser-ablatingact forms a plurality of conductive leads 340, 342 and a plurality oftest-sensor contacts 344, 346. The conductive leads 340, 342 assist inestablishing electrical communication between the electrodes and thetest-sensor contacts 344, 346. The test-sensor contacts 344, 346 areelectrically connected with meter contacts (not shown) and assist inconveying information of the analyte to the meter to assist in, forexample, determining the analyte concentration.

In this method, after the electrode pattern 328 is formed, dielectricmaterial 350 is placed over the electrode pattern as depicted in FIG. 4d. The dielectric material 350 insulates the electrode pattern 328.Referring to FIG. 4 e, selected areas of the dielectric material 350 arelaser ablated to expose at least a portion of the electrodes. In FIG. 4e, the dielectric material 350 in this process is also laser ablated toexpose the test-sensor contacts 344, 346. The exposed electrode portionsare shown as generally circular areas 330 a, 332 a, 334 a in FIG. 4 e.It is contemplated that other polygonal and non-polygonal shapes of theelectrodes may be exposed by the laser ablation as well as formingmultiple patterns on one electrode.

In this method, two separate and distinct laser-ablation acts areperformed. After the exposure of the electrodes in the secondlaser-ablation act, a second layer is applied. For example, in FIG. 4 f,a spacer 360 is attached to the dielectric material 350. In FIG. 4 g, alid 370 is attached to the spacer 360. The lid 370, the spacer 360 andthe dielectric material 350 assist in forming an opening 372 (see FIG. 4i) to receive a fluid.

It is contemplated that the plurality of electrodes may be defined onthe base by other methods such as, for example, printing (e.g.,screen-printing, gravure or ink-jet printing), coating (e.g., reverseroll, slot die), vapor deposition, sputtering and electrochemicaldeposition. For example, referring to FIG. 5 a, a base or substrate 380may be provided. As shown in FIG. 3 b, the electrode pattern 382 may beadded to the base 380 by, for example, printing, coating, vapordeposition, sputtering or electrochemical deposition. The electrodepattern 382 includes a plurality of electrodes 384, 386, 388, aplurality of conductive leads 390, 392 and a plurality of test-sensorcontacts 394, 396. After the electrode pattern 382 is formed on the base380, the process may continue by performing the acts discussed above inconnection with FIGS. 3 d-3 h to form an electrochemical test sensor. Inanother process, after the electrode pattern 382 is formed on the base380, the process may continue by performing the acts discussed above inconnection with FIGS. 4 d-4 i to form an electrochemical test sensor.

According to another method, an electrochemical test sensor may beformed by initially providing a base or substrate.Electrochemically-active material is placed on the base. Dielectricmaterial is applied over the electrochemically-active material. Thus, inthis method an electrode pattern is not created before the dielectricmaterial is applied to the electrochemically-active material. A firstselected area of the dielectric material is laser-ablated to expose theelectrochemically-active material. A second selected area of thedielectric material is laser ablated and the electrochemically-activematerial to expose the base. The first selected area is different fromthe second selected area. A second layer is applied to assist in forminga channel (e.g., capillary channel) in the test sensor. The capillarychannel assists in allowing a fluid sample to contact a reagent locatedtherein. The dielectric material is located between the base and thesecond layer.

Referring to FIG. 6 a-6 i, a method of forming an electrochemical testsensor 400 is depicted. Referring to FIGS. 6 a, 6 b, a base or substrate410 is shown in which electrochemically-active material 420 has beenplaced thereon. As shown in FIG. 6 a, the electrochemically-activematerial 420 covers the entire base 410 in this embodiment. Referring toFIGS. 6 c, 6 d, dielectric material 450 is placed over theelectrochemically-active material 420. After the dielectric material 450is placed over the electrochemically-active material 420, twolaser-ablation acts are formed.

As shown in FIG. 6 e, a first laser-ablation act extends through thedielectric material 450 and the electrochemically-active material 420and forms a plurality of lines 412, 414. Thus, the plurality of lines412, 414 extends to the substrate 410. The plurality of lines 412, 414forms outer boundaries of the plurality of electrodes, conductive leadsand test-sensor contact boundaries in this embodiment. Morespecifically, the plurality of electrodes in this embodiment includes acounter electrode 430, a working electrode 432, and a trigger electrode434. As with the other embodiments, the plurality of electrodes may varyin number. Typically, the plurality of electrodes includes at leastworking and counter electrodes.

Referring to FIG. 6 f, a second laser-ablation act extends only throughthe dielectric material 450 at selected areas 430 a, 432 a, 434 a thatwill be exposed to the fluid sample. It is contemplated that the areas430 a, 432 a, 434 a may be of other shapes than depicted in FIG. 6 f.The second laser-ablation act also forms a plurality of test-sensorcontacts 444, 446. Thus, the second laser-ablation act extends only tothe electrochemically-active material 420. In one method, the firstlaser-ablation act and the second laser-ablation act are performed usingdifferent pulses at different intensities. Thus, the secondlaser-ablation act may be operated at a lower power intensity. Thesesteps may be performed by multiple lasers, a single laser that includessplit beams or a single laser at different times. It is contemplatedthat the first and second laser ablation acts may be reversed insequence. For example, the selected area 430 a, 432 a, 434 a may beformed before the plurality of lines 412, 414.

After the exposure of the electrodes in the laser-ablation act, a secondlayer is applied. For example, in FIGS. 6 g-6 i, a lid 470 is attachedto the dielectric material 450 and forms an opening 472 (see FIG. 6 i)to receive a fluid.

Referring to FIG. 7 a-7 i, a method of forming an electrochemical testsensor 500 is depicted. Referring to FIGS. 7 a, 7 b, a base or substrate510 is shown in which electrochemically-active material 520 has beenplaced thereon. As shown in FIG. 7 a, the electrochemically-activematerial 520 covers the entire base 510 in this embodiment. Referring toFIGS. 7 c, 7 d, dielectric material 550 is placed over theelectrochemically-active material 520. After the dielectric material 550is placed over the electrochemically-active material 520, twolaser-ablation acts are formed.

As shown in FIG. 7 e, a first laser-ablation act extends through thedielectric material 550 and the electrochemically-active material 520and forms a plurality of lines 512, 514. Thus, the plurality of lines512, 514 extends to the substrate 510. The plurality of lines 512, 514forms outer boundaries of the plurality of electrodes, conductive leadsand test-sensor contact boundaries in this embodiment. Morespecifically, the plurality of electrodes in this embodiment includes acounter electrode 530, a working electrode 532, and a trigger electrode534. As with the other embodiments, the plurality of electrodes may varyin number. Typically, the plurality of electrodes includes at leastworking and counter electrodes.

Referring to FIG. 7 f, a second laser-ablation act extends only throughthe dielectric material 550 at selected areas 530 a, 532 a, 534 a thatwill be exposed to the fluid sample. It is contemplated that the areas530 a, 532 a, 534 a may be of other shapes than depicted in FIG. 7 f.The second laser-ablation act also forms a plurality of test-sensorcontacts 544, 546. Thus, the second laser-ablation act extends only tothe electrochemically-active material 520. In one method, the firstlaser-ablation act and the second laser-ablation act are performed usingdifferent pulses at different intensities. Thus, the secondlaser-ablation act may be operated at a lower power intensity. Thesesteps may be performed by multiple lasers, a single laser that includessplit beams or a single laser at different times. It is contemplatedthat the first and second laser ablation acts may be reversed insequence. For example, the selected area 530 a, 532 a, 534 a may beformed before the plurality of lines 512, 514. After the exposure of theelectrodes in the laser-ablation act, a second layer is applied.

As shown in FIG. 7 g, a spacer 560 is added to the dielectric layer 550.As shown in FIGS. 7 h-7 j, a lid 570 is attached to the spacer 560 andthe lid 570, spacer 560 and the dielectric material 550 assist informing an opening 572 (see FIG. 7 j) to receive a fluid.

PROCESS A

A method of forming an electrochemical test sensor, the methodcomprising the acts of:

-   -   providing a base;    -   placing electrochemically-active material on the base;    -   laser-ablating the electrochemically-active material to form an        electrode pattern;    -   applying dielectric material over the electrode pattern;    -   laser-ablating selected areas of the dielectric material to        expose a portion of the electrode pattern; and    -   applying a second layer to assist in forming a channel in the        test sensor, the channel assisting in allowing a fluid sample to        contact a reagent located therein,    -   wherein the dielectric material is located between the base and        the second layer.

PROCESS B

The method of alternative process A wherein the laser-ablating of theselected areas further exposes meter contacts on the test sensor.

PROCESS C

The method of alternative process A wherein the second layer is a lid.

PROCESS D

The method of alternative process A wherein the second layer is a spacerand further includes applying a lid to the spacer so as to define thechannel, the spacer being located between the lid and the base.

PROCESS E

The method of alternative process A wherein the second layer is aspacer-lid combination.

PROCESS F

The method of alternative process A wherein the electrochemically-activematerial is a metallic conductive material.

PROCESS G

The method of alternative process A wherein the reagent includes glucoseoxidase or glucose dehydrogenase.

PROCESS H

The method of alternative process A wherein the channel is a capillarychannel.

PROCESS I

A method of forming an electrochemical test sensor, the methodcomprising the acts of:

-   -   providing a base;    -   forming an electrode pattern on the base;    -   applying dielectric material over the electrode pattern;    -   laser-ablating selected areas of the dielectric material to        expose a portion of the electrode pattern; and    -   applying a second layer to assist in forming a channel in the        test sensor, the channel assisting in allowing a fluid sample to        contact a reagent located therein,    -   wherein the dielectric material is located between the base and        the second layer.

PROCESS J

The method of alternative process I wherein the electrode pattern isformed by printing, coating, vapor deposition, sputtering orelectrochemical deposition.

PROCESS K

The method of alternative process J wherein the electrode pattern isformed by printing.

PROCESS L

The method of alternative process I wherein the second layer is a lid.

PROCESS M

The method of alternative process I wherein the second layer is a spacerand further includes applying a lid to the spacer so as to define thechannel, the spacer being located between the lid and the base.

PROCESS N

The method of alternative process I wherein the second layer is aspacer-lid combination.

PROCESS O

A method of forming an electrochemical test sensor, the methodcomprising the acts of:

-   -   providing a base;    -   placing electrochemically-active material on the base;    -   applying dielectric material over the electrochemically-active        material;    -   laser-ablating a first selected area of the dielectric material        to expose the electrochemically-active material;    -   laser-ablating a second selected area of the dielectric material        and the electrochemically-active material to expose the base,        the first selected area being different from the second selected        area; and    -   applying a second layer to assist in forming a channel in the        test sensor, the channel assisting in allowing a fluid sample to        contact a reagent located therein,    -   wherein the dielectric material is located between the base and        the second layer.

PROCESS P

The method of alternative process O wherein the laser-ablating of theselected areas further exposes meter contacts on the test sensor.

PROCESS Q

The method of alternative process O wherein the second layer is a lid.

PROCESS R

The method of alternative process O wherein the second layer is a spacerand further includes applying a lid to the spacer so as to define thechannel, the spacer being located between the lid and the base.

PROCESS S

The method of alternative process O wherein the second layer is aspacer-lid combination.

PROCESS T

The method of alternative process O wherein the electrochemically-activematerial is a metallic conductive material.

PROCESS U

The method of alternative process O wherein the reagent includes glucoseoxidase or glucose dehydrogenase.

PROCESS V

The method of alternative process O wherein the channel is a capillarychannel.

While the present invention has been described with reference to one ormore particular embodiments, those skilled in the art will recognizethat many changes may be made thereto without departing from the spiritand scope of the present invention. Each of these embodiments, andobvious variations thereof, is contemplated as falling within the spiritand scope of the invention.

1. A method of forming an electrochemical test sensor, the methodcomprising the acts of: providing a base; placingelectrochemically-active material on the base; laser-ablating theelectrochemically-active material to form an electrode pattern; applyingdielectric material over the electrode pattern; laser-ablating selectedareas of the dielectric material to expose a portion of the electrodepattern; and applying a second layer to assist in forming a channel inthe test sensor, the channel assisting in allowing a fluid sample tocontact a reagent located therein, wherein the dielectric material islocated between the base and the second layer.
 2. The method of claim 1wherein the laser-ablating of the selected areas further exposes metercontacts on the test sensor.
 3. The method of claim 1 wherein the secondlayer is a lid.
 4. The method of claim 1 wherein the second layer is aspacer and further includes applying a lid to the spacer so as to definethe channel, the spacer being located between the lid and the base. 5.The method of claim 1 wherein the second layer is a spacer-lidcombination.
 6. The method of claim 1 wherein theelectrochemically-active material is a metallic conductive material. 7.The method of claim 1 wherein the reagent includes glucose oxidase orglucose dehydrogenase.
 8. The method of claim 1 wherein the channel is acapillary channel.
 9. A method of forming an electrochemical testsensor, the method comprising the acts of: providing a base; forming anelectrode pattern on the base; applying dielectric material over theelectrode pattern; laser-ablating selected areas of the dielectricmaterial to expose a portion of the electrode pattern; and applying asecond layer to assist in forming a channel in the test sensor, thechannel assisting in allowing a fluid sample to contact a reagentlocated therein, wherein the dielectric material is located between thebase and the second layer.
 10. The method of claim 9 wherein theelectrode pattern is formed by printing, coating, vapor deposition,sputtering or electrochemical deposition.
 11. The method of claim 10wherein the electrode pattern is formed by printing.
 12. The method ofclaim 9 wherein the second layer is a lid.
 13. The method of claim 9wherein the second layer is a spacer and further includes applying a lidto the spacer so as to define the channel, the spacer being locatedbetween the lid and the base.
 14. The method of claim 9 wherein thesecond layer is a spacer-lid combination.
 15. A method of forming anelectrochemical test sensor, the method comprising the acts of:providing a base; placing electrochemically-active material on the base;applying dielectric material over the electrochemically-active material;laser-ablating a first selected area of the dielectric material toexpose the electrochemically-active material; laser-ablating a secondselected area of the dielectric material and theelectrochemically-active material to expose the base, the first selectedarea being different from the second selected area; and applying asecond layer to assist in forming a channel in the test sensor, thechannel assisting in allowing a fluid sample to contact a reagentlocated therein, wherein the dielectric material is located between thebase and the second layer.
 16. The method of claim 15 wherein thelaser-ablating of the selected areas further exposes meter contacts onthe test sensor.
 17. The method of claim 15 wherein the second layer isa lid.
 18. The method of claim 15 wherein the second layer is a spacerand further includes applying a lid to the spacer so as to define thechannel, the spacer being located between the lid and the base. 19.(canceled)
 20. The method of claim 15 wherein theelectrochemically-active material is a metallic conductive material. 21.The method of claim 15 wherein the reagent includes glucose oxidase orglucose dehydrogenase.
 22. (canceled)